Greenlake is very very swimmer friendly. The water is clean and gets over 70 degrees in summer. Algae growth and closures were sometimes a problem before the City of Seattle performed a comprehensive cleanup in 2004. It is now one of the cleanest public swimming areas in the Seattle area.

King County's Swimming Beach Monitoring Program shows current conditions at several swimming beaches, and West Greenlake's water quality in particular.

West Greenlake

Sample Date Fecal Coliform Temperature (C) Temperature (F) 7/28/2009 10 25.0 77.0 7/21/2009 13 24.0 75.0 7/14/2009 6 21.0 69.0 7/7/2009 15 21.0 70.0 6/29/2009 1 21.0 70.0 6/23/2009 7 21.0 70.0 6/15/2009 79 22.0 72.0 6/9/2009 68 22.0 72.0 6/2/2009 7 22.0 72.0 5/26/2009 23 19.0 65.0 5/18/2009 8 18.0 64.0 5/12/2009 5 15.0 59.0

Fecal Coliform Mean 7 6 9 14 12 23 23 13 -99 -99 -99 -99